Mapping computer systems (“mapping systems”) display digital geographic imagery of the Earth at varying perspectives including providing users an oblique view (e.g. bird's eye-view) of objects on the surface of the Earth such as houses, buildings, roads, lakes, mountains, and the like. Such geographic imagery may comprise satellite imagery, aerial photography, and the like. Since the Earth is a curved generally spherical object, the geographic images are rectified by the mapping systems so that the mapping systems can project the images onto a two-dimensional (2-D) plane such as a computer display screen.
Mapping systems may use a coordinate system to identify a point on the surface of the Earth. One common coordinate system is geographic coordinates (latitude/longitude) on the World Geodetic System of 1984 (WGS84) datum. Latitude is an angular measurement in degrees ranging from 0 degrees at the Earth's equator to 90 degrees at the poles. Longitude is also an angular measurement but measured East or West instead of North or South. For example, the location of White House in Washington D.C. on the surface of the Earth as identified by a geographic coordinate is 38.898748 degrees latitude and −77.037684 degrees longitude.
It is often desirable to associate a geographic location with a piece of data and then display the data as a superimposition on digital geographic imagery. For example, it may be desirable to associate a geographic location with a street address such that when a map image of the street is displayed the address can be visually indicated by superimposing the text of the address, a symbol or other indicator on the map at the geographic location. The process of associating a geographic location with a piece of data, typically in the form of geographic coordinates (e.g., latitude/longitude), is known as geotagging. One approach for geotagging typically involves a user identifying the geographic coordinates of a particular location using a mapping system and then manually entering the coordinates into a database containing the one piece of data that is to be geotagged. However, this manual approach is awkward and inconvenient for the user and is a serious drawback for organizations that require geotagging of many thousands or many millions of pieces of data.
The approaches described in this section are approaches that could be pursued, but not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated, it should not be assumed that any of the approaches described in this section qualify as prior art merely by virtue of their inclusion in this section.